As multimedia age arrives, the resolution of a display apparatus becomes more important than ever. Generally, multimedia apparatuses, especially for video purposes, are divided into two groups. One group emits light actively and the other emits light passively. The active group includes CRT (Cathode Ray Tube) and LED (Light Emitting Diode). The passive group includes LCD (Liquid Crystal Display).
LCD technology is the main stream technology utilized in display apparatuses today. Its advantages include power saving and small dimensions when compare to the traditional CRT technology. It is well known to those skilled in the art that a colorful LCD display apparatus utilizes a LCD panel comprising a plurality of TFT transistors, a polarizer, and a light source for generating colorful images. TFT transistors can be used as controllers to control images on colorful display apparatus composed of red, green and blue pixels. To construct display or non-display status of display pixels in the specific area on a TFT panel, a driver circuit first controls a plurality of data signals. The driver circuit then scans signals to drive the pixels located in a specific area on the TFT panel. Finally, the driver circuit utilizes TFT transistors to activate the “on” state or “off” state of the pixels.
An active matrix LCD display utilizes a TFT substrate as a base to develop pixels and as a conjunction for driving current to pass by. Thus, it has the advantages of small dimensions and reduced manufacturing cost, e.g., PCB boards used for connection. The TFT substrate further comprises TFT transistors, each of which controls an LCD pixel. Each TFT transistor comprises a gate terminal coupled with a scan line, a source terminal coupled with a data line, and a drain terminal coupled with an anode of the LCD pixel. The cathode of the LCD pixel may be connected to ground. When the scan line is driven by a high voltage, the transistor is switched on. Then, the data line provides a specific voltage to the source terminal of the TFT transistor and then to the anode of the LCD pixel.
To drive the voltage of the data line into the LCD pixel for displaying images, the LCD display apparatus further comprises drivers whose main function is to output appropriate voltages into pixels to control the “twisting” of liquid crystal molecules. Generally, there are two types of drivers: one is a gate driver positioned along the X axis of the display apparatus and the other is a source driver positioned along the Y axis. The function of the source driver is to input data signals. The function of the gate driver is to twist the liquid crystal molecules.
Because of market demand, the resolution of LCD display apparatus needs to be better than ever. More gate drivers are needed to support high resolution LCD. For example, an LCD display apparatus with resolution 1366×768 requires three gate drivers; each contains two hundred and fifty six channels. Please refer to FIG. 1 which illustrates a gate driver structure for an LCD display apparatus in the prior art. The structure of the LCD display apparatus comprises a first gate driver 102, a second gate driver 104, a third gate driver 106, and a substrate 108 on which a plurality of TFT transistors is grown. The material of the substrate 108 may be glass or transparent insulating materials like polyester resin, polyimide etc. The first gate driver 102, positioned on a FPC (Flexible Printed Circuit Board) (not shown), is coupled to the substrate 108. The first gate driver 102 comprises a first pad (STV1) to receive a trigger voltage signal, and a two hundred and fifty six channels including a first channel D_CH1, a second channel D_CH2, a third channel D_CH3, . . . , and a two hundred and fifty sixth channel D_CH256. In addition, the gate driver 102 also outputs a trigger voltage signal from a second pad (STV2). By driving voltages via the first channel D_CH1, the second channel D_CH2, the third channel D_CH3, . . . , and the two hundred and fifty sixth channel D_CH256, to a first horizontal channel P_CH1, a second horizontal channel P_CH2, a third horizontal channel P_CH3, . . . , and a two hundred and fifty sixth horizontal channel P_CH256, on the substrate 108 respectively, there will be two hundred and fifty six horizontal outputs from the gate driver 102. Similarly, a second gate driver 104 comprises a first pad (STV1) to receive a trigger voltage signal, and a two hundred and fifty six channels including a two hundred and fifty seventh channel D_CH257, a two hundred and fifty eighth channel D_CH258, a two hundred and fifty ninth channel D_CH259, . . . , and a five hundred and twelfth channel D_CH512. Furthermore, the gate driver 104 outputs another trigger voltage signal from a second pad (STV2). By driving voltages via the two hundred and fifty seventh channel D_CH257, the two hundred and fifty eighth channel D_CH258, the two hundred and fifty ninth channel D_CH259, . . . , and the five hundred and twelfth channel D_CH512, to a two hundred and fifty seventh horizontal channel P_CH257, a two hundred and fifty eighth horizontal channel P_CH258, a two hundred and fifty ninth horizontal channel P_CH259, . . . , and a five hundred and twelfth horizontal channel P_CH512, on the substrate 108 respectively, there are additional two hundred and fifty six horizontal outputs from the gate driver 104. The third gate driver 106 also performs a similar function. A second gate driver 106 comprises a first pad (STV1) to receive a trigger voltage signal and a two hundred and fifty six channels including a five hundred and thirteenth channel D_CH513, a five hundred and fourteenth channel D_CH514, a five hundred and fifteenth channel D_CH515, . . . , and a seven hundred and sixty eighth channel D_CH768. The gate driver 106 outputs another trigger voltage signal from a second pad (STV2). By driving voltages via the five hundred and thirteenth channel D_CH513, the five hundred and fourteenth channel D_CH514, the five hundred and fifteenth channel D_CH515, . . . , and the seven hundred and sixty eighth channel D_CH768, to a five hundred and thirteenth horizontal channel P_CH513, a five hundred and fourteenth horizontal channel P_CH514, a five hundred and fifteenth horizontal channel P_CH515, . . . , and a seven hundred and sixty eighth horizontal channel P_CH768, on the substrate 108 respectively, there are another two hundred and fifty six horizontal outputs from the gate driver 106.
In effect, the demands for higher resolution on LCD display increases the number of gate drivers required, and raises the costs and inefficiencies in the manufacturing processes.